Tool having rotatable member for machining an object and sensor to sense object

ABSTRACT

A tool for machining an object comprising: a first part including a rotatable member, the rotatable member being rotatable to cause rotation of a machine tool; a second part; a joint coupling the first part and the second part to enable relative movement between the first part and the second part; and a sensor to sense an object to be machined.

TECHNOLOGICAL FIELD

The present disclosure concerns a tool for machining an object.

BACKGROUND

Gas turbine engines may be used, for example, to propel aircraft and/orto generate electrical energy. FIG. 1 illustrates an example of a gasturbine engine 10 having a principal and rotational axis 11. The engine10 comprises, in axial flow series, an air intake 12, a propulsive fan13, an intermediate pressure compressor 14, a high-pressure compressor15, combustion equipment 16, a high-pressure turbine 17, andintermediate pressure turbine 18, a low-pressure turbine 19 and anexhaust nozzle 20. A nacelle 21 generally surrounds the engine 10 anddefines both the intake 12 and the exhaust nozzle 20.

The gas turbine engine 10 works in the conventional manner so that airentering the intake 12 is accelerated by the fan 13 to produce two airflows: a first air flow into the intermediate pressure compressor 14 anda second air flow which passes through a bypass duct 22 to providepropulsive thrust. The intermediate pressure compressor 14 compressesthe air flow directed into it before delivering that air to the highpressure compressor 15 where further compression takes place.

The compressed air exhausted from the high-pressure compressor 15 isdirected into the combustion equipment 16 where it is mixed with fueland the mixture combusted. The resultant hot combustion products thenexpand through, and thereby drive the high, intermediate andlow-pressure turbines 17, 18, 19 before being exhausted through thenozzle 20 to provide additional propulsive thrust. The high 17,intermediate 18 and low 19 pressure turbines drive respectively the highpressure compressor 15, intermediate pressure compressor 14 and fan 13,each by suitable interconnecting shaft.

Gas turbine engines may require maintenance and repair during theiroperational life. For example, a fan blade or a compressor blade of agas turbine engine may become damaged during operation (for example, thefan or compressor blade may become chipped) and such damage may impairthe performance of the gas turbine engine. A highly skilled engineer maybe required to perform the repair. However, such repair may be costlyand/or may not be performed in a timely manner where the gas turbineengine is located remote from a repair centre.

BRIEF SUMMARY

According to various examples there is provided a tool for machining anobject, the tool comprising: a first part including a rotatable member,the rotatable member being rotatable to cause rotation of a machinetool; a second part; a joint coupling the first part and the second partto enable relative movement between the first part and the second part;and a sensor to sense an object to be machined.

The sensor may be configured to provide image data and/or measurementdata of the object to be machined.

The second part may comprise the sensor.

The second part may comprise a cover defining an aperture. The sensormay be positioned within the cover and adjacent to the aperture.

The tool may further comprise an energy transmission member extendingbetween the first part and the second part and across the joint. Theenergy transmission member may be arranged to provide energy to therotatable member to cause rotation of the rotatable member.

The energy transmission member may comprise a conduit to provide fluidto the rotatable member.

The energy transmission member may comprise an electrical cable toprovide electrical energy to the rotatable member.

The rotatable member may comprise a turbine.

The rotatable member may comprise an electrical motor.

The joint may comprise one or more cables coupled to the first part. Theone or more cables may be moveable relative to the second part to enablethe first part to be moved relative to the second part.

The tool may further comprise a machine tool coupled to the rotatablemember to receive torque from the rotatable member.

The machine tool may comprise a blending tool.

According to various examples there is provided apparatus comprising: acontroller to: receive data from the sensor of a tool; determine controlof the tool using the received data; and provide a control signal tocause control of the tool. In some embodiments, the tool may bestructured as described in any of the preceding paragraphs. In otherembodiments, the tool may have an alternative structure and may be aninspection apparatus and include, for example, a Raman spectrometer, animaging device (such as a camera) or an Ultraviolet (UV) inspectiondevice.

The controller may be to determine whether relative movement between thetool and the object is required to enable machining of the object by thetool.

The controller may be to determine control of the tool by: determiningwhether the object has a shape that differs from a predetermined shapeabove a threshold level; and determining a machining path for the toolto bring the shape of the object at least towards conformity with thepredetermined shape.

The controller may be to determine whether the object has a shape aftermachining that differs from the predetermined shape above a thresholdlevel; and determining a further machining path for the tool to bringthe shape of the object further towards conformity with thepredetermined shape.

The controller may be configured to operate without user intervention.

The controller may comprise a first controller and a second controller.The first controller may be to determine the control of the tool. Thesecond controller may be to provide the control signal to the tool tocontrol the apparatus. The first controller may communicate withmultiple second controllers at a time in a multi-device configuration.

The second controller may be located in closer proximity to the toolthan the first controller.

The first controller may be configured to receive data from the sensor.The first controller may be configured to provide the data to the secondcontroller. The second controller may be configured to determine amachining path for the tool.

The second controller may be to receive the machining path from thefirst controller. The second controller may be to convert the machiningpath into control signals to control the tool.

The apparatus may further comprise an actuator to receive the controlsignals from the controller and to control the tool using the controlsignals.

According to various examples there is provided a method comprising:receiving data from the sensor of the tool as described in any of thepreceding paragraphs; determining control of the tool using the receiveddata; and providing a control signal to cause control of the tool.

The method may further comprise determining whether relative movementbetween the tool and the object is required to enable machining of theobject by the tool.

Determining control of the tool may include determining whether theobject has a shape that differs from a predetermined shape; anddetermining a machining path for the tool to bring the shape of theobject at least towards conformity with the predetermined shape where itis determined that the shape of the object differs from thepredetermined shape.

The method may further comprise determining whether the object has ashape after machining that differs from the predetermined shape; anddetermining a further machining path for the tool to bring the shape ofthe object further towards conformity with the predetermined shape whereit is determined that the machined shape of the object differs from thepredetermined shape.

The method may be performed without user intervention.

According to various examples there is provided a computer program that,when read by a computer, causes performance of the method as describedin any of the preceding paragraphs.

According to various examples there is provided a non-transitorycomputer readable storage medium comprising computer readableinstructions that, when read by a computer, causes performance of themethod as described in any of the preceding paragraphs.

The skilled person will appreciate that except where mutually exclusive,a feature described in relation to any one of the above aspects may beapplied mutatis mutandis to any other aspect.

BRIEF DESCRIPTION

Examples will now be described with reference to the Figures, in which:

FIG. 1 illustrates a cross sectional side view of a gas turbine engine;

FIG. 2 illustrates a schematic diagram of a tool according to variousexamples;

FIG. 3 illustrates a sectional perspective view of a tool according tovarious examples;

FIG. 4 illustrates a perspective view of the exterior of the toolillustrated in FIG. 3;

FIG. 5 illustrates a perspective view of second part of the toolillustrated in FIGS. 3 and 4;

FIG. 6 illustrates a schematic diagram of apparatus for controllingmachining according to various examples;

FIG. 7 illustrates a flow diagram of a method of controlling machiningaccording to various examples;

FIG. 8 illustrates a schematic diagram of another apparatus forcontrolling machining according to various examples; and

FIG. 9 illustrates a flow diagram of another method of controllingmachining according to various examples.

DETAILED DESCRIPTION

In the following description, the terms ‘connected’ and ‘coupled’ meanoperationally connected and coupled. It should be appreciated that theremay be any number of intervening components between the mentionedfeatures, including no intervening components.

FIG. 2 illustrates a schematic diagram of a tool 24 for machining anobject 26. The tool 24 may be any suitable apparatus or device formachining the object 26. For example, the tool 24 may be any suitablerotary machine tool, and may be, for example, a blending tool, agrinding tool, or a drilling tool. The tool 24 includes a first part 28,a second part 30, a joint 32, an (optional) energy transmission member34, a sensor 36, and a rotatable member 38 to cause rotation of amachine tool. The object 26 may be any object to be machined. Forexample, the object 26 may be a component of a gas turbine engine, andmay be a blade or a vane of a gas turbine engine.

The first part 28 includes the rotatable member 38 and may include afirst cover 40 for at least partially covering the rotatable member 38.The first cover 40 may have any suitable shape and define a cavity forreceiving the rotatable member 38 therein. For example, the first cover40 may have a circular cross sectional shape, an elliptical crosssectional shape, a square cross sectional shape or a rectangular crosssectional shape.

The second part 30 may include a second cover 42 for at least partiallycovering one or more components of the tool 24. The second cover 42 mayhave any suitable shape and define a cavity for receiving the one ormore components therein. For example, the second cover 42 may have acircular cross sectional shape, an elliptical cross sectional shape, asquare cross sectional shape, or a rectangular cross sectional shape.

The joint 32 is arranged to couple the first part 28 and the second part30 to enable relative movement between the first part 28 and the secondpart 30. The joint 32 may comprise any suitable structure and maycomprise, for example, a pivot joint, a hinge, or a resilient materialinterconnecting the first part 28 and the second part 30. In someexamples, the joint 32 may comprise a plurality of joints that may havethe same structure or a different structure to one another.

The rotatable member 38 may be any suitable apparatus or device to causerotation of a machine tool (such as a blending tool). For example, therotatable member 38 may include a turbine or an electrical motor. Therotatable member 38 may include, or be coupled to, a chuck for receivinga machine tool to provide torque to the machine tool.

The energy transmission member 34 extends between the first part 28 andthe second part 30 and across the joint 32. The energy transmissionmember 34 is arranged to provide energy to the rotatable member 38 tocause rotation of the rotatable member 38. For example, where therotatable member 38 comprises a turbine, the energy transmission member34 may comprise a conduit to provide fluid to the turbine 38 to causerotation of the rotatable member 38. By way of another example, wherethe rotatable member 38 is an electrical motor, the energy transmissionmember 34 may comprise one or more electrical cables to provideelectrical energy to the electrical motor 38.

The sensor 36 may comprise any suitable sensor, or plurality of sensors,to sense the object 26 to be machined. The sensor 36 may comprise one ormore sensors (such as one or more of, or any combination of:tachometers, inertial measurement units (IMU), inertial navigationsystems (INS), encoders, torque meters, shape sensors, accelerometers)to sense one or more states of the tool 24, such as orientation,position, shape, velocity, acceleration, torque, and so on. The sensor36 may additionally or alternatively comprise one or more sensors (suchas one or more of, or any combination of: force sensors, strain gauges,pressure sensors, bending sensors, proximity sensors, imaging sensors,temperature sensors, humidity sensors, radiation detection sensors andso on) to sense one or more states external to the tool 24, such asforce, strain, pressure, bend temperature, humidity, radiation, distanceto an external object, size of an external object, material of anexternal object, and shape and orientation of an external object.

In some examples, the sensor 36 may be at least partially positionedwithin the second cover 42 of the second part 30. In such examples, thesecond cover 42 may define an aperture and the sensor 36 may bepositioned adjacent the aperture to enable the sensor 36 to sense one ormore states external to the tool 24.

FIGS. 3 and 4 illustrate perspective views of another tool 241 accordingto various examples. The tool 241 is similar to the tool 24 and wherethe features are similar, the same reference numerals are used.Consequently, the tool 241 includes a first part 28, a second part 30, ajoint 32, a conduit 34, a sensor 36, and a rotatable member 38. Thefirst part 28 has a first longitudinal axis 43 that extends along thelength of the first part 28, and the second part 30 has a secondlongitudinal axis 45 that extends along the length of the second part30.

The tool 241 differs from the tool 24 in that the first part 40 furthercomprises a chuck 44 and a blending tool 46. Additionally, the joint 32includes a first joint 48 (a cable pull joint in this example) and asecond joint 50 (a pivot joint in this example).

The second cover 42 has a cylindrical shape and defines an aperture 52there through (which may also be referred to as a ‘window’). The sensor36 is positioned within the second cover 42 and adjacent to the aperture52 to enable the sensor 36 to sense one or more states external to thetool 241. As illustrated in FIG. 5, the second cover 42 also defines afluid flow passage 53 there within that extends along the length of thesecond cover 42 and is arranged to receive fluid (such as air) from asource and to provide the fluid to the conduit 34. Additionally, thesecond cover 42 defines one or more holes 55 that extend along thelength of the second cover 42 and are arranged to receive one or morecables 54 there within. The fluid flow passage 53 and the one or moreholes 55 are positioned around the perimeter of the second cover 42which advantageously provides sufficient space within the second cover42 for the sensor 36.

The first joint 48 comprises one or more cables 54, a plurality of discs56 and a plurality of flexible interconnectors 58. The one or morecables 54 are coupled to the first part 28 and are moveable relative tothe second part 30 to enable the first part 28 to be moved relative tothe second part 30. The plurality of flexible interconnectors 58interconnect the discs 56 and enable the discs to pivot relative to oneanother so that the first part 28 may extend radially outwards from thelongitudinal axis 43. The plurality of discs 56 define one or more holesthat extend through the discs 56 and are arranged to receive the one ormore cables 54 there within. The one or more cables 54 are slidablewithin the one or more holes of the second cover 42 and the plurality ofdiscs 56 respectively. In some examples, one or more of the cables 54may not be directly connected to the first part 28 and may instead beconnected to one or more of the discs 56.

The second joint 50 (not illustrated in FIG. 3 to maintain the clarityof the figure) is a pivot joint and includes a pair of arms 60 thatextend towards the first part 28 from the disc 56 that is adjacent tothe first part 28. The arms 60 are pivotally coupled to the first part28 via pins 62. The first part 28 may be pivoted relative to the secondpart 30 at the second joint 50 via actuation of the one or more cables54 so that the first longitudinal axis 43 of the first part 28 extendsradially outwards from the longitudinal axis 43 (as illustrated in FIG.4).

The first cover 40 of the first part 28 has a cylindrical shape andhouses the rotatable member 38 that is coupled to the blending tool 46via the chuck 44. The rotatable member 38 includes fluid guide channels64 and a turbine 66 that is coupled to the chuck 44. The fluid guidechannels 64 are fixed in position relative to the first cover 40 (thatis, the fluid guide channels 64 are a static part within the first cover40) and are arranged to receive fluid from the conduit 34. The turbine66 is arranged to receive fluid from the fluid guide channels 64 and torotate about the first longitudinal axis 43 relative to the first cover40.

In operation, the fluid flow passage in the second cover 42 receivesfluid (such as air) from a source (such as a pressurized air container).The fluid then flows to the turbine 66 via the conduit 34 and the fluidguide channels 64. The flow of fluid through the turbine 66 causes theturbine 66 to rotate about the first longitudinal axis 43 and thus drivethe chuck 44 and the machine tool 46 to rotate about the firstlongitudinal axis 43.

The tool 24, 241 may provide several advantages. First, the rotatablemember 38 may be arranged to rotate at relatively high speed and thetool 24, 241 may consequently require a lower force to machine theobject 26. For example, where the rotatable member 38 includes a turbine(such as the turbine 66), the turbine may rotate at 200,000 to 400,000RPM. Second, the inclusion of the sensor 36 may enable an operator ofthe tool 24, 241 to inspect and measure the object 26 during machining.This may significantly reduce the time required to machine the object 26relative to the use of a machining tool and separate sensing device. Forexample, where the object 26 is a blade within a gas turbine engine andthe tool 24, 241 is a blending tool, use of the tool 24, 241 may reducethe time required to blend the blade by up to fifty times. Third, thepositioning of the fluid flow passage 53 and the holes 55 mayadvantageously enable sufficient fluid to be provided to the turbine 66and enable the sensor 36 to be positioned within the second cover 42.This may advantageously reduce the size of the tool 24, 241 and enablethe tool 24, 241 to be inserted into relatively narrow spaces within amechanical system.

FIG. 6 illustrates a schematic diagram of apparatus 68 for controllingmachining according to various examples. The apparatus 68 includes acontroller 70, an actuator 71, a user input device 72, an output device73, and the tool 24, 241. In some examples, the apparatus 68 may be asingle, unitary device where the controller 70, the actuator 71, theuser input device 72, the output device 73, and the tool 24, 241 arephysically coupled together. In other examples, the apparatus 68 may bean apparatus that is distributed across a plurality of differentlocations (for example, the apparatus 68 may be distributed acrossdifferent cities, different counties or different countries).

In some examples, the apparatus 68 may be a module. As used herein, thewording ‘module’ refers to a device or apparatus where one or morefeatures are included at a later time, and possibly, by anothermanufacturer or by an end user. For example, where the apparatus 68 is amodule, the apparatus 68 may only include the controller 70, and theremaining features may be added by another manufacturer, or by an enduser.

The controller 70 may comprise any suitable circuitry to causeperformance of the methods described herein and as illustrated in FIGS.7 & 9. The controller 70 may comprise any of, or combination of:application specific integrated circuits (ASIC); field programmable gatearrays (FPGA); single or multi-processor architectures; sequential (VonNeumann)/parallel architectures; programmable logic controllers (PLCs);microprocessors; and microcontrollers, to perform the methods.

By way of an example, the controller 70 may comprise at least oneprocessor 74 and at least one memory 76. The memory 76 stores a computerprogram 78 comprising computer readable instructions that, when read bythe processor 74, causes performance of the methods described herein,and as illustrated in FIGS. 7 & 9. The computer program 78 may besoftware or firmware, or may be a combination of software and firmware.

The processor 74 may be located on the tool 24, 241, or may be locatedremote from the tool 24, 241, or may be distributed between the tool 24,241 and a location remote from the tool 24, 241. The processor 74 mayinclude at least one microprocessor and may comprise a single coreprocessor, or may comprise multiple processor cores (such as a dual coreprocessor or a quad core processor).

The memory 76 may be located on the tool 24, 241, or may be locatedremote from the tool 24, 241, or may be distributed between the tool 24,241 and a location remote from the tool 24, 241. The memory 76 may beany suitable non-transitory computer readable storage medium, datastorage device or devices, and may comprise a hard disk and/or solidstate memory (such as flash memory). The memory 76 may be permanentnon-removable memory, or may be removable memory (such as a universalserial bus (USB) flash drive).

The computer program 78 may be stored on a non-transitory computerreadable storage medium 80. The computer program 78 may be transferredfrom the non-transitory computer readable storage medium 80 to thememory 76. The non-transitory computer readable storage medium 80 maybe, for example, a USB flash drive, a compact disc (CD), a digitalversatile disc (DVD) or a Blu-ray disc. In some examples, the computerprogram 78 may be transferred to the memory 76 via a wireless signal 82or via a wired signal 82.

The actuator 71 may comprise any suitable device or devices forcontrolling the tool 24, 241. For example, the actuator 71 may compriseone or more servomotors that are coupled to the one or more cables 54 ofthe tool 241 to move the first part 28 relative to the second part 30.The actuator 71 may also comprise a fluid source (such as a compressedair container) that is arranged to provide fluid to the fluid flowpassages of the second cover 42. The controller 70 is configured toprovide control signals to the actuator 71 to control the operation ofthe actuator 71.

The sensor 36 of the tool 24, 241 is arranged to receive control signalsfrom the controller 70 that control the operation of the sensor 36. Forexample, where the sensor 36 includes an imaging device (such as a CCDor CMOS camera), the controller 70 may be configured to control theoptical zoom and/or focal point of the imaging device. The sensor 36 isarranged to provide signals to the controller 70 for the sensed state ofthe tool 24, 241 and/or for the sensed external state of the tool 24,241.

The user input device 72 may be any suitable device, or devices, forenabling a user to control the apparatus 68. For example, the user inputdevice 72 may comprise one or more of, or any combination of: akeyboard, a keypad, a touchscreen display, a computer mouse, and atouchpad. The controller 70 is configured to receive user input controlsignals from the user input device 72.

The output device 73 may be any suitable device for presentinginformation to a user of the apparatus 68. The output device 73 maycomprise a display (such as a liquid crystal display (LCD), a lightemitting diode (LED) display, or a thin film transistor (TFT) displayfor example). The controller 70 may be configured to cause control ofthe display to display images. For example, the controller 70 mayreceive image data from the sensor 36 of the tool 24, 241 and then causecontrol of the display of the output device 73 to display an image usingthe received image data. The output device 73 may additionally oralternatively comprise a loudspeaker to provide acoustic waves to theuser of the apparatus 68 and the controller 70 may be configured tocause control of the loudspeaker to provide acoustic waves. In someexamples, the output device 73 may include an actuator that may be usedto rotate a rotor of a gas turbine engine to position the object 26.

The operation of the apparatus 68 is described in the followingparagraphs with reference to FIG. 7.

At block 84, the method starts and a user may mount at least the tool24, 241 on a mechanical system such as a gas turbine engine. The usermay initialise the apparatus 68 by operating the user input device 72.For example, where the user input device 72 includes a power switch, theuser may initialise the apparatus 68 by pressing the power switch tosupply electrical energy to the apparatus 68. By way of another example,the user may initialise the apparatus 68 by interacting with a graphicaluser interface displayed on a display of the output device 73 using theuser input device 72 to execute the computer program 78.

At block 86, the method includes receiving data from the sensor 36 ofthe tool 24, 241. For example, the data may include image data from thesensor 36 for the view out of the aperture 52. The controller 70 mayreceive the data from the sensor 36 and cause control of the outputdevice 73 to present information to the user using the received data.For example, where the controller 70 receives image data from the sensor36, the controller 70 may cause control of a display of the output 73 todisplay the image in the image data.

At block 88, the method includes determining whether relative movementbetween the tool 24, 241 and the object 26 is required to enablemachining of the object 26 by the tool 24, 241. For example, thecontroller 70 may analyse image data received in block 86 to determinewhether the object 26 to be machined is positioned at a predeterminedposition and/or orientation relative to the tool 24, 241. By way ofanother example, where the sensor 36 includes an ultrasonic sensor fortransmitting and sensing ultrasonic acoustic waves, the controller 70may analyse data from the ultrasonic sensor to determine whether theobject 26 to be machined is positioned at a predetermined positionand/or orientation relative to the tool 24, 241.

Where the controller 70 determines that the object 26 is not positionedat the predetermined position and/or orientation, the controller 70determines that relative movement between the tool 24, 241 and theobject 26 is required to enable machining of the object 26. Thecontroller 70 may then cause control of the output device 73 to presentinformation to the user of the apparatus 68 to inform the user to movethe object 26 and/or the tool 24, 241. For example, where the object 26is a fan blade or a compressor blade, the controller 70 may causecontrol of the output device 73 to present information to the user toinform the user to move the fan blade or compressor by a certain anglein either the clockwise or anticlockwise direction. In some examples,the controller 70 may provide a control signal to the tool 24, 241and/or the object 26 to cause the tool 24, 241 and/or the object 26 tomove relative to one another (for example, the tool 24, 241 may includerobotics that enable the tool 24, 241 to move relative to the object 26to the predetermined position).

Block 88 may then be repeated until the controller 70 determines thatthe object 26 is positioned at the predetermined position and/ororientation relative to the tool 24, 241. Where the controller 70determines that the object 26 is positioned at the predeterminedposition and/or orientation relative to the tool 24, 241, the methodmoves to block 90.

At block 90, the method includes determining whether the object 26 has ashape that differs from a predetermined shape to determine whether theobject 26 is damaged. The memory 76 may store predetermined shapes forone or more different objects. In some examples, the controller 70 maycompare the similarity of the sensed shape of the object 26 with thepredetermined shape of the object stored in the memory 76 to determinewhether the similarity is below a threshold similarity value. By way ofanother example, the controller 70 may compare the differences betweenthe sensed shape of the object 26 and the predetermined shape of theobject stored in the memory 76 to determine whether the difference isabove a threshold difference value.

For example, a predetermined shape of the compressor blade may be storedin the memory 76. The controller 70 may compare the similarity of thesensed shape of the compressor blade with the predetermined shape of thecompressor blade stored in the memory 76 to determine whether thesimilarity is below a threshold similarity value.

Where the controller 70 determines that the shape of the object 26 doesnot differ from (or is similar to) the predetermined shape of the object26, the method may return to block 86 for another different object.Where no further objects are to be machined, the method moves to block102 and is ended. Where the controller 70 determines that the shape ofthe object 26 differs from (or is not similar to) the predeterminedshape of the object 26, the method moves to block 92.

At block 92, the method includes determining a machining path for thetool 24, 241 to bring the shape of the object 26 at least towardsconformity with the predetermined shape. In some examples, thedetermined machining path for the tool 24, 241 is generated to bring theshape of the object 26 into full conformity with the predetermined shape(that is, so that they have the same shape after machining). Accordingto various examples, a machining path may be determined by generating asurface from the damaged site using the sensor 36 (for example, bycreating a mesh from point cloud data). Then, using a pre-set scallopgeometry (one of either a tip blend, or a normal scallop blend), a toolpath is matched to the size required by the user. This tool path is thenbroken into a number of steps to provide an iterative formation of theshape. A collision check is then performed using the inverse kinematicsof the controller 70 to ascertain if the tool 24, 241 will collide withanything, and if not, the method moves to block 94. The controller 70may store the generated machining path in the memory 76.

At block 94, the method includes providing a control signal to causecontrol of the tool 24, 241. The controller 70 may use the machiningpath generated at block 92 to cause control of the tool 24, 241 tomachine the object 26. For example, the controller 70 may convert themachining path into a control signal to cause control of the tool 24,241. In some examples, the controller 70 may directly control the tool24, 241 to machine the object 26. In other examples, the controller 70may indirectly control the tool 24, 241 by sending a control signal toone or more other controllers that then directly control the tool 24,241 (in other words, there may be one or more other controllers in thecontrol path between the controller 70 and the tool 24, 241).

At block 96, the method includes determining whether the object 26 has ashape after machining that differs from the predetermined shape. Forexample, the controller 70 may receive data from the sensor 36 of thetool 24, 241 for the machined object 26 and then use that data todetermine whether the shape of the object 26 is below a thresholdsimilarity value when compared with the predetermined shape, or may usethat data to determine whether the shape of the object 26 is above athreshold difference value when compared with the predetermined shape.

Where the controller 70 determines that the shape of the machined object26 does not differ from (or is similar to) the predetermined shape ofthe object 26, the method may return to block 86 for another differentobject. Where no further objects are to be machined, the method moves toblock 102 and is ended.

Where the controller 70 determines that the shape of the machined object26 differs from (or is not similar to) the predetermined shape of theobject 26, the method moves to block 98.

At block 98, the method includes determining a further machining pathfor the tool 24, 241 to bring the shape of the object 26 further towardsconformity with the predetermined shape.

At block 100, the method includes providing a control signal to causecontrol of the tool 24, 241. The controller 70 may use the machiningpath generated at block 98 to cause control of the tool 24, 241 tofurther machine the object 26. In some examples, the controller 70 maydirectly control the tool 24, 241 to machine the object 26. In otherexamples, the controller 70 may indirectly control the tool 24, 241 bysending a control signal to one or more other controllers that thendirectly control the tool 24, 241.

The method then returns to block 96 to determine whether the object 26has a shape after machining that differs from the predetermined shape.Where the controller 70 determines that the shape of the machined object26 does not differ from (or is similar to) the predetermined shape ofthe object 26, the method may return to block 86 for another, differentobject. Where no further objects are to be machined, the method moves toblock 102 and is ended. Where the controller 70 determines that theshape of the machined object 26 differs from (or is not similar to) thepredetermined shape of the object 26, the method moves to block 98.

The apparatus 68 may provide several advantages. For example, theapparatus 68 may enable a machining operation (such as blending forexample) to be performed automatically by the controller 70 and withouthuman intervention. This may enable repair quality to be standardised.Additionally, the output device 73 may advantageously enable an operatorto visually inspect the damaged component of the mechanical systemduring and after machining.

FIG. 8 illustrates a schematic diagram of another apparatus 104 forcontrolling machining according to various examples. The apparatus 104includes a first controller 106, a second controller 108, the actuator71, the tool 24, 241, and a mechanical system 110. The apparatus 104 issimilar to the apparatus 68 illustrated in FIG. 6 and where the featuresare similar, the same reference numerals are used.

The first controller 106 may be referred to as a ‘high level controller(HLC)’ and may comprise a structure as described in the precedingparagraphs for the controller 70. The controller 106 may include avirtual reality simulator (VRS), a graphical user interface (GUI), adatabase, and a high level control communicator (HLCC) that includes asecure protocol engine and command processor. The first controller 106is located in a first zone 112 and may also be connected to a user inputdevice 72 and an output device 73 as illustrated in FIG. 6.

The second controller 108 may be referred to as a ‘low level controller(LLC)’ and may comprise a structure as described in the precedingparagraphs for the controller 70. The controller 108 may include a toolcontroller, a graphical user interface (GUI), and a low level controlcommunicator (LLCC) that includes a secure protocol engine and commandprocessor. The second controller 108 is located in a second zone 114 andmay also be connected to a user input device 72 and an output device 73as illustrated in FIG. 6.

The actuator 71, tool 24, 241 and the mechanical system 110 are locatedin a third zone 116. In some examples, the mechanical system 110 is agas turbine engine and may be structured as illustrated in FIG. 1 (inother words, the gas turbine engine may be a three shaft gas turbineengine 10 as illustrated in FIG. 1).

The first controller 106, the second controller 108, the actuator 71 andthe tool 24, 241 may be connected to one another via any suitablenetwork that includes wired connections and/or wireless connections. Forexample, the first controller 106 and the second controller 108 may becoupled to one another via a wired connection (for example, viaintercontinental data cables) or via a wireless connection (for example,via a satellite connection). By way of another example, the secondcontroller 108 and the tool 24, 241 may be coupled to one another via awired connection (for example, via an Ethernet cable) or via a wirelessconnection (for examples, via a local wireless area network (WEAN)).

The first zone 112, the second zone 114, and the third zone 116 mayrepresent different locations. For example, the first zone 112, thesecond zone 114, and the third zone 116 may represent differentcountries, states, counties, or cities. By way of an example, the firstzone 112 may represent a control centre in a first country, the secondzone 114 may represent a control centre in a second country, and thethird zone 116 may represent an aircraft maintenance hangar in thesecond country. In some examples, the second zone 114 and the third zone116 may be the same location and consequently, the second controller 108may be located in closer proximity to the tool 24, 241 than the firstcontroller 106. For example, the first zone 112 may represent a controlcentre in a first country, and the second and third zones 114, 116 mayrepresent an aircraft maintenance hangar in a second country.

The operation of the apparatus 104 is described in the followingparagraphs with reference to FIG. 9.

At block 118, the method includes installation of the tool 24, 241(referred to as the blending instrument/robot in FIG. 9) on themechanical system 110 by the local operator.

At block 120, the method includes establishing a data connection betweenthe first controller 106 and the second controller 108.

At block 122, the method includes calibrating the tool 24, 241. Forexample, the second controller 108 may calibrate the tool 24, 241 usingdata stored at the second controller 108.

At block 124, the method includes obtaining measurements of an object 26of the mechanical system 110. For example, block 124 may includeobtaining measurements of a damaged turbine blade of a gas turbineengine. Block 124 may be performed by the second controller 108.

At block 126, the method includes providing a definition of the desiredblend specifications, which may be performed by the first controller106.

At block 128, the method includes generating a blending path, which maybe performed by the first controller 106. For example, the firstcontroller 106 may receive the measurements from the second controller108 and then use the received measurements and the blend specificationprovided in block 126 to generate a blending path.

At block 130, the method includes conversion of the blending path totool motion control signals, which may be performed by the secondcontroller 108. For example, the second controller 108 may receive thegenerated blending path from the first controller 106 and then convertthe blending path to tool motion control signals.

At block 132, the method includes performing the defined blendingoperation, which may be performed by the second controller 108, theactuator 71, and the tool 24, 241. For example, the second controller108 may provide the tool motion control signals to the actuator 71 andto the tool 24, 241 to control blending of the damaged turbine blade.

At block 134, the method includes measuring the performed blend, whichmay be performed by the second controller 108. For example, the secondcontroller 108 may receive data from the sensor 36 of the tool 24, 241and use the received data to measure the blend.

At block 136, the method includes comparing the performed blend and thedesired blend. For example, the first controller 106 may receivemeasurement data from the second controller 108 (determined in block134) and use the received measurement data to compare the performedblend and the desired blend. Where the performed blend does not matchthe desired blend, the method returns to block 128 and the firstcontroller 106 generates a new blending path. Where the performed blendmatches the desired blend and another object requires blending, themethod returns to block 124. Where the performed blend matches thedesired blend and no further objects require blending, the method movesto block 138.

At block 138, the method includes terminating the connection between thefirst controller 106 and the second controller 108.

At block 140, the method includes uninstalling the tool 24, 241 from themechanical system 110 by the local operator.

The apparatus 104 may provide several advantages. For example, there aretypically few operators who are sufficiently skilled and experienced toperform blending on internal components of a gas turbine engine. Theapparatus 104 may advantageously enable such operators to monitor and/orcontrol blending remotely (for example, through interaction with thefirst controller 106) and without being required to travel to the gasturbine engine. In other words, the operator may remain in the firstzone 112 and monitor and/or control blending of damaged gas turbineengine components in other zones (such as the third zone 116). This mayadvantageously enable the operator to repair a greater number ofcomponents and may also advantageously reduce the cost of blendingoperations (since the operator may spend less time and money ontravelling).

It will be understood that the various apparatus and methods are notlimited to the embodiments above-described and various modifications andimprovements can be made without departing from the concepts describedherein. For example, the tool 24, 241 may not include a rotatable memberand machine head and may instead include one or more of: a laser head,an imaging sensor (for example, a charge coupled device camera), a Ramanspectrometer, a fluorescent penetrant applicator, and an ultraviolet(UV) inspection device.

Except where mutually exclusive, any of the features may be employedseparately or in combination with any other features and the disclosureextends to and includes all combinations and sub-combinations of one ormore features described herein.

The invention claimed is:
 1. A tool for machining an object, the toolcomprising: a first part including a rotatable member, the rotatablemember being rotatable to cause rotation of a machine tool; a secondpart including: a cover having an aperture and forming a fluid flowpassage having an arcuate cross-section and extending longitudinallythrough the cover; and a sensor positioned within the cover and adjacentto the aperture and the fluid flow passage, the sensor being configuredto sense the object to be machined; and a joint coupling the first partand the second part to enable relative movement between the first partand the second part.
 2. The tool as claimed in claim 1, wherein thesensor is configured to provide image data and/or measurement data ofthe object to be machined.
 3. The tool as claimed in claim 1, furthercomprising an energy transmission member extending between the firstpart and the second part and across the joint, the energy transmissionmember being arranged to provide energy to the rotatable member to causerotation of the rotatable member.
 4. The tool as claimed in claim 3,wherein the energy transmission member includes a conduit to providefluid to the rotatable member.
 5. The tool as claimed in claim 1,wherein the rotatable member includes a turbine.
 6. The tool as claimedin claim 1, wherein the joint includes one or more cables coupled to thefirst part, the one or more cables being moveable relative to the secondpart to enable the first part to be moved relative to the second part.7. The tool as claimed in claim 1, wherein the machine tool is coupledto the rotatable member and receives torque from the rotatable member.8. The tool as claimed in claim 7, wherein the machine tool includes ablending tool.
 9. An apparatus for controlling machining, the apparatuscomprising: a controller configured to: receive data from the sensor ofthe tool as claimed in claim 1; determine control of the tool using thereceived data; and provide a control signal to cause control of thetool.
 10. The apparatus as claimed in claim 9, wherein the controller isconfigured to determine whether relative movement between the tool andthe object is required to enable machining of the object by the tool.11. The apparatus as claimed in claim 9, wherein the controller isconfigured to determine control of the tool by: determining whether theobject has a shape that differs from a predetermined shape above athreshold level; and determining a machining path for the tool to bringthe shape of the object at least towards conformity with thepredetermined shape.
 12. The apparatus as claimed in claim 11, whereinthe controller is configured to: determine whether the object has ashape after machining that differs from the predetermined shape abovethe threshold level; and determine a further machining path for the toolto bring the shape of the object further towards conformity with thepredetermined shape.
 13. The apparatus as claimed in claim 9, whereinthe controller is configured to operate without user intervention. 14.The apparatus as claimed in claim 9, wherein the controller includes afirst controller and a second controller, the first controllerdetermines the control of the tool, and the second controller providesthe control signal to the tool to control the apparatus.
 15. Theapparatus as claimed in claim 14, wherein the second controller islocated in closer proximity to the tool than the first controller. 16.The apparatus as claimed in claim 14, wherein: the first controller isconfigured to: receive data from the sensor, and provide the data to thesecond controller, and the second controller is configured to determinea machining path for the tool.
 17. The apparatus as claimed in claim 16,wherein the second controller is configured to: receive the machiningpath from the first controller, and convert the machining path intocontrol signals to control the tool.
 18. A method of controllingmachining, the method comprising: receiving data from the sensor of thetool as claimed in claim 1; determining control of the tool using thereceived data; and providing a control signal to cause control of thetool.